This is an artistic impression of a Sunset from Barnard's star. It is the closest single star to the sun and second closest stellar system only to the Alpha Centauri triple star system. Astronomers have long tried to find around exoplanets. Barnard's Star, the planet's host star, is a red dwarf, a cool, low-mass star, which only dimly illuminates this newly-discovered world.
In a landmark discovery, an worldwide team of astronomers led by Ignasi Ribas of the Institute of Space Studies of Catalonia (IEEC) and Institute of Space Sciences (IEEC- CSIC) has found a candidate planet orbiting Barnard's star.
The super-Earth orbits Barnard's star every 233 days, and is at least 3.2 times the mass of the Earth (hence the term).
If the planet can be observed directly it will provide vital information about its properties and extend our understanding of the kinds of planets that form around red dwarf stars.
The newly detected planet orbiting Barnard's Star may not be so hospitable, with surface temperatures of perhaps minus 274 degrees Fahrenheit (minus 170 degrees Celsius). Knowing that we have one of these unusual exoplanets so nearby could allow us to get to know this planetary species a little better. As it moves towards Earth its light appears shifted towards the blue part of the spectrum and, as it moves away, it appears shifted towards the red.
As scientists hope that the first pictures will be received already in the running GAIA mission, and the telescope WFIRST and "James Webb", which NASA will take into space early next decade. This makes Barnard's Star b a prime candidate for us to use powerful spectroscopic techniques to, one day, peer into its atmosphere (if it has one) and understand what it's really made of.
Ribas and his team used 800 different observations of Barnard's Star to drive down the uncertainty that the planet existed. The radial velocity method looks for gravitational changes as a planet pushes or pulls on its star. They watched for small counter movements in the star that indicate a massive body (a planet) is in orbit.
'We knew we would have to be patient.
Might that have happened at Barnard's star?
Graphic representation of the relative distances to the nearest stars from the sun.
Because Barnard's star is so close, the separation between the planet and star in the sky will be relatively large.
To find Barnard´s Star b, Ribas and the team studied more than 20 years´ worth of observations from seven separate instruments. "[The candidate] is very strong in terms of the statistical significance". (There was one approach that suggested the signal wasn't real, but that analysis is known to produce false negative results.) The strength of the signal also increased as new observations were added, reinforcing indications that it's real. The "planets", however, ended up being nothing more than an instrumentation problem with the Sproul Observatory in Swarthmore, Pennsylvania, whose director, Peter van de Kamp, first claimed the existence of planets around the star. "The combination of all data led to a total of 771 measurements", Ribas said.
"When we re-analyzed all the combined measurements, a clear signal arose at a period of 233 days".
Bernard's Star b has been categorized as a Super-Earth, meaning its mass is higher than Earth's, but doesn't reach the massive mass of ice giants like Uranus (15 times Earth's mass) and Neptune (17 times Earth's mass). The closest lies just over four light-years from Earth and was also discovered by a team led by Queen Mary's Dr. Anglada Escudé in 2016.